1. Field of the Invention
The present invention relates to a method for producing a capacitor with a precise capacitance and, more particularly, to a method for producing a film capacitor which is directly formed on a circuit board.
2. Description of the Prior Art
Electronic components have recently become considerably compact in size and thin in thickness. This is a result of high integration of active elements and compact passive and functional elements.
For example, techniques for forming film resistors directly on a substrate have been proposed and carried out. These film resistors are formed in the following manner. A substrate is applied with a thick film paste containing ruthenium oxide as a major component or an organic thick film paste containing carbon as a major component. The resultant film is baked or subjected to a thin film forming technique such as deposition, sputtering or plating. In such film resistors, a mounting process required for chip components is not needed, resulting in a simple process and low cost.
Film capacitors using a thick film paste have been proposed. For example, a dielectric paste and a metal powder paste for an electrode are alternately printed and baked so as to form the film capacitor. However, a capacitance of the resultant capacitor changes slightly in accordance with a thickness of the paste and printing and baking conditions. Therefore, it is difficult to produce a capacitor having a designed capacitance.
This problem occurs not only with film capacitors, but also with normal chip capacitors which are influenced by the manufacturing process. Therefore, it is very difficult to obtain a designed capacitance.
In other words, only after the final step in the manufacture of these capacitors is completed, a capacitance thereof can be determined.